Drilling unit

ABSTRACT

A drilling unit is provided with a top drive which is mobile along a drilling axis in order to move drilling rods, with two telescopic drilling masts which are arranged facing each other, a cable device and a hydraulic device which co-operate with each other to move the top drive along a support guide which is parallel to the axis and is arranged in an intermediate position in relation to the two drilling masts for supporting and sliding the top drive along the axis. A hydraulic actuator for each drilling mast is suitable for modifying a longitudinal length of the relative drilling mast. A control station is suitable for controlling the actuation of each hydraulic actuator either in simultaneous or independent fashion.

BACKGROUND OF THE INVENTION

The present invention refers to a drilling unit.

In general, drilling units of a well known kind comprise a drillingmast; a top drive which is supported in sliding fashion by the mastitself in order to move the drilling rods; and a movement group for thetop drive.

In drilling units of the kind which have been described above, thedrilling mast is a telescopic mast which is defined by a fixed trellisand a sliding trellis which is inside the fixed trellis, and themovement group comprises a cable device which is provided with at leasta pair of hanging sheaves which are arranged at the head of the slidingtrellis, and a hydraulic device which is suitable for modifying thelength of the telescopic mast in order to move the top drive along thetelescopic mast itself.

Drilling units of the above-described kind have always beenadvantageously used because they are practical to move and to installeven in places which are rather impractical, but the increasinglypressing operating demands which have been imposed in the drillingsector in general, and in the sector of drilling for oil in particular,have lead to a progressive increase in the power which is required ofthese units in terms of reaching their structural and functional limits.It has in fact been noted that in order to increase the developed powerwhich is available to the movement group it would be necessary toconstruct a telescopic mast of such dimensions that would not onlythwart the above-mentioned characteristics of agility, but would alsorender extremely difficult the use of the hydraulic devices which arecurrently available on the market to the detriment, in addition, ofproduction costs.

SUMMARY OF THE INVENTION

The aim of the present invention is to produce a drilling unit which,while maintaining characteristics of agility in terms of positioning,will also be able to support levels of operating power which are greaterthan current ones, and which will not involve high levels of costs interms of production, planning or engineering.

According to the present invention a drilling unit will be producedcomprising a top drive which is mobile along a drilling axis in order tomove drilling rods, and a movement group of the top drive comprising, inits turn, a cable device and a hydraulic device which co-operates withthe cable device in order to move the top drive along the drilling axis;the unit comprising two drilling masts which are arranged facing andparallel to each other and a support guide which is arranged side byside and in an intermediate position in relation to the two drillingmasts in order to support and slide the top drive along the drillingaxis; the hydraulic device being provided with a hydraulic actuator foreach drilling mast which is suitable for modifying a longitudinal lengthof the drilling mast itself, and with a control station for theactuation of the hydraulic actuator either in contemporary orindependent fashion.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described with reference to theattached drawings, which illustrate a non-limiting form of embodiment ofthe present invention, in which:

FIG. 1 illustrates a lateral elevation of a preferred form of embodimentof the drilling unit according to the present invention; and

FIG. 2 illustrates from above, with some parts removed for reasons ofclarity, the unit which is shown in FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

With reference to the attached drawings, the number 1 indicates in itsentirety a drilling unit for the drilling of oil wells.

The unit 1 comprises a support structure 2 which is defined, in the formof embodiment which is described, by two lateral bases 3 which may bepositioned on substructures or others and by a central frame 4, which isconnected to both the bases 3, and which is raised in relation to thebases 3 themselves.

In addition, the unit 1 comprises a support guide 5 which is positionedon the central frame parallel and frontally to a drilling axis A, andtwo drilling masts 6, which are arranged opposite the axis A and theguide 5, and which rise from the frame 4 parallel to the guide 5 itself.Each drilling mast 6 is a telescopic mast which is defined by a fixedtrellis 6′ which is hinged to the base 3 in order to rotate around arespective axis B which is transverse to the axis A under the action ofa jack 7 which is interposed between the trellis 6′ itself and therelative lateral base 3, and by a trellis 6″ which is inserted inlongitudinally sliding fashion inside the trellis 6′ itself, and whichis provided with an upper head 8.

In FIG. 1, the drilling masts 6 are shown in their closed operatingcondition, in which the length of each mast 6 is substantially equal tothe length of the relative trellis 6′, as well as in a possibleelongated operating condition, in which the length of each mast 6 issubstantially equal to the sum of the length of the relative trellis 6′plus the length of the relative trellis 6″. In the case in which themasts 6 are completely elongated, the overall length of each of thesewill be substantially equal to the length of the guide 5 measured fromthe starting point of the frame 4.

Finally, the unit 1 comprises a top drive 10 which is supported insliding fashion by the guide 5 by means of interposing a trolley 11 inorder to move the drilling rods along the axis A, and a movement group20 of the top drive 10 which comprises, in its turn, a cable device 30and a hydraulic device 40 which co-operates with the device 30 in orderto move the top drive 10 along the axis A.

The trolley 11 is coupled to the guide 5 in order to slide along theguide 5 itself parallel to the axis A, and the top drive 10 comprises arod moving sleeve 12, which is arranged co-axial to the axis A and isconnected to the trolley 11 in order to slide along the axis A itself.The top drive 10 is suitable for being moved along the guide 5 startingfrom its own lower dead point which corresponds to the closed operatingcondition of both the two masts 6, as far as its own upper dead pointwhich corresponds to the elongated operating condition of both the masts6.

The cable device 30 comprises four pulls of cable 31 a, which are eachfixed, at their own opposite ends, to respective dead ends 32, and, foreach pull 31, four pairs of hanging sheaves 33 which are arranged inpairs on the head 8 of each mast 6, and a pair of hanging sheaves 34which are mounted on the trolley.

The hanging sheaves 33 and 34 are all loose pulleys which are suitablefor rotating around respective rotation axes which are parallel to eachother, and, in particular, the two hanging sheaves 33 of each pair oneach head 8 are arranged facing the hanging sheaves 33 of the otherthree pairs of the same head 8, and, equally, the two hanging sheaves 34of each pair on the trolley 11 are arranged facing the hanging sheaves34 of the other three pairs which are supported by the trolley 11 itselfin such a way as to arrange the four pulls 31 parallel to each other andin the same dynamic conditions.

The device 30 comprises, in addition, two balancing systems 35, each ofwhich is arranged in correspondence with a respective side of each base3, and comprises an equaliser 36 which is hinged to the base 3 in orderto rotate around an own axis which is parallel to the axis B, and twogripping elements 37, which are each connected to an end 32 in such away that an end 32 of a pull 31 is opposed on the equaliser 36 to an end32 of the immediately adjacent pull 31.

In other words, the cable 31 a of each pull 31 is engaged by a relativeelement 37, and extends upwards along the relative mast 6 in order towind around a pair of hanging sheaves 33 and return downwards to wind,this time, around a pair of hanging sheaves 34; then return upwardsalong the other mast 6 in order to wind around the other pair of hangingsheaves 33 and descend along the same mast 6 to be engaged by the otherelement 37.

The hydraulic device 40 comprises two hydraulic cylinders 41, each ofwhich presents an engine power which is equal to the engine power of theother cylinder 41, and is interposed between a relative fixed trellis 6′and the corresponding mobile trellis 6″ in order to modify the length ofthe relative telescopic mast 6 in such a way as to move the top drive 10along the support guide 5.

Each cylinder 41 extends inside the trellises 6′ and 6″, and presents arespective rod which is connected at the top to the relative head 8, andat the bottom is inserted inside a casing 41 b which is, instead,integral with the trellis 6′. In addition, each cylinder 41 is connectedto a control station 42, which is part of the device 40, and which issuitable for controlling the activation of the two cylinders 41 eitherin contemporary fashion or independently of each other. In the form ofembodiment which is herein described and in the attached drawings, thecontrol station 42 has been generalised and schematicised for reasons ofsimplicity, being a control station which is normally used in hydrauliccircuits for controlling relative components.

In use, starting from the closed operative position, the activation ofeach cylinder 41 determines the elongation along the axis A of therelative mast 6, or rather the upward movement of the relative hangingsheave 33. As the length of the cables 31 a of each pull 31 is fixed,and the cables 31 a are blocked at both their ends in correspondencewith the balancing systems 35, the elongation of the two masts 6determines the raising of the top drive 10 along the guide 3 with theadvantage that, in the case that the activation of the two cylinders 41is not contemporary, the power which is delivered by each cylinder 41 inorder to raise the top drive 10 is, in proportion, equal to half of thepower which can be delivered by the cylinders 41 in the case that theyfunction in contemporary fashion.

Consequently, it is obvious that the presence of the two cylinders 41and the layout of the unit 1 which has been described above enables thesupply of an overall power which is double that which may be supplied byeach mast 6 on an individual basis without the need to double thedimensions of the mast 6 itself.

In addition, the unit 1 which has been described above may equallyfunction in the case of damage to or failure of one of the two cylinders41, permitting, however, the continuation of the drilling operations andthe repair of the damage or failure.

It is intended that the present invention should not be limited to theforms of embodiment which are herein described and illustrated, whichare to be considered as examples of forms of embodiment of the drillingunit, and which may instead be subject to further modifications relatingto the shape and disposition of its parts, as well as to detailspertaining to construction and assembly.

1. Drilling unit comprising a top drive which is mobile along a drillingaxis to move drilling rods, and a movement group of the top drivecomprising a cable device and a hydraulic device co-operating with thecable device to move the top drive along the drilling axis; the unitcomprising two drilling masts arranged facing and parallel to each otherand a support guide arranged side by side and in an intermediateposition in relation to the two drilling masts to support and slide thetop drive along the drilling axis; the hydraulic device being providedwith a hydraulic actuator for each drilling mast suitable for modifyinga longitudinal length of the drilling mast, and with a control stationfor the actuation of the hydraulic actuators either in simultaneous orindependent fashion.
 2. Drilling unit according to claim 1, wherein eachdrilling mast comprises a telescopic mast having a fixed trellis and asliding trellis inside the fixed trellis; the relative hydraulicactuator being interposed between the fixed trellis and the mobiletrellis to modify the length of the telescopic mast in such a way as tomove the top drive along the support guide.
 3. Drilling unit accordingto claim 2, wherein the cable device is provided with at least a pair ofhanging sheaves for each drilling mast arranged at the head of therelative mobile trellis, and with at least an additional pair of hangingsheaves associated with the top drive.
 4. Drilling unit according toclaim 3, comprising a trolley coupled in sliding fashion along the guideto support the top drive and the relative pair of hanging sheaves. 5.Drilling unit according to claim 4, wherein the cable device comprisesat least a double pull of cables, each of which is fixed at its ownopposite ends to respective dead ends and which winds around arespective pair of hanging sheaves of each telescopic mast and around arespective pair of hanging sheaves of the top drive.
 6. Drilling unitaccording to claim 5, wherein the hydraulic actuators comprise relativehydraulic cylinders.
 7. Drilling unit according to claim 6, wherein thehydraulic cylinders present equal entities of engine power.
 8. Drillingunit according to claim 1 comprising a support structure on which aremounted the drilling masts and the support guide.